I keep getting a syntax erring in my code?

[superchew]

Private Sub WorkSheet_Change(ByVal Target As Range)

Dim txtLocation As String
Dim txtExtension As String
Dim txtFileName As String
Dim response As Integer

Set Target = Range("D1")

txtLocation = "D:\picking logs\"         'Change this to the location for the files always with a \ at end
txtExtension = ".xls"      'The extention for the file
txtFileName = txtLocation & "Batch " & Target & txtExtension

'lets check of the file exists
    If ThisWorkbook.FullName = txtFileName Then
        'if the above is true then save the workbook
        Application.DisplayAlerts = False
            ThisWorkbook.Save
        Application.DisplayAlerts = True
    Else
        On Error GoTo Err1
        ThisWorkbook.SaveAs Filename:=txtFileName
    End If

Exit Sub
   
Err1:
MsgBox "An error has occurred. Make sure the directory in the macro is valid." & _
    ActiveSheet.Protect "hi"
        
End Sub

I keep getting a syntax erro for this code please help.